193 F.3d 545 (D.C. Cir. 1999)
Roy Dale Richardson, Appellantv.United States of America, et al.,Appellees
No. 98-5176 Consolidated with 98-5236
United States Court of AppealsFOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued October 5, 1999Decided October 22, 1999

Appeals from the United States District Court for the District of Columbia(No. 97cv01962)
Kimberlee Cleaveland, Student Counsel, argued the cause  as amicus curiae for appellant.  On the briefs were Steven H.  Goldblatt, appointed by the court, and Todd Coltman, Nikhil  Singhvi and Olivier Sylvain, Student Counsel.
Roy Dale Richardson, appearing pro se, was on the briefs  for appellant.
Somesha Ferdinand, Attorney, U.S. Department of Justice,  argued the cause for appellees. With her on the brief were  David W. Ogden, Acting Assistant Attorney General, Jeffrey  Axelrad and Mary McElroy Leach, Attorneys, and Wilma A.  Lewis, U.S. Attorney.
Before:  Edwards, Chief Judge, Wald and Williams,  Circuit Judges.
Opinion for the Court filed by Chief Judge Harry T. Edwards.
Harry T. Edwards, Chief Judge:


1
Roy Richardson brought this action  under the Federal Tort Claims Act ("FTCA") and Swine Flu  Act for injuries allegedly suffered as a result of his 1976  swine flu vaccination while serving in the United States Air  Force.  The District Court dismissed Mr. Richardson's pro se  complaint for lack of subject matter jurisdiction, holding that  his allegation fell within the discretionary function exception  to the FTCA.  See 28 U.S.C. § 2680(a) (1994).  Subsequently,  the court denied Mr. Richardson's motion for reconsideration  and for leave to amend the complaint.


2
On the record before us, we find that Mr. Richardson  effectively amended his complaint when he filed a timely  response to the Government's motion to dismiss.  The amended complaint easily satisfied liberal pleading requirements,  for it made clear that Mr. Richardson was not seeking  compensation for tortious acts or omissions of military personnel, but, rather, for the vaccine manufacturer's alleged  tortious conduct in producing a defective vaccine.  Indeed,  Mr. Richardson specifically cited Hunt v. United States, 636  F.2d 580 (D.C. Cir. 1980), in asserting that his claim was  based on the defective or negligent manufacturing of the  vaccine.  Because Mr. Richardson effectively amended his  complaint to state a legitimate claim over which the District  Court had subject matter jurisdiction, we must reverse the  trial court's judgment dismissing his complaint.  In light of  this holding, we have no need to reach Mr. Richardson's  argument that the District Court abused its discretion by failing to grant him leave to amend his complaint after it was  dismissed.

I. Background

3
On November 19, 1976, while Roy Dale Richardson was on  active duty with the U.S. Air Force at Tinker Air Force Base,  in Oklahoma City, Oklahoma, military personnel ordered him  to be vaccinated with the swine flu vaccine.  Richardson  alleges that he suffered a "near toxic allergic reaction" to the  vaccine, causing him to be hospitalized for four days, and that  hospital tests conducted at that time revealed a "mitral valve  leak" and hypertension.  See Complaint pp 11, 17, reprinted  in App. to Br. of Amicus Curiae ("App.") 6-7.  Mr. Richardson was honorably discharged on May 16, 1977.


4
Mr. Richardson claims that he did not become aware of the  full extent of his vaccine-caused injuries until April 1995, at  which time he was awarded Veteran's Administration disability compensation.  He alleges that his injuries are varied,  including kidney stones, numerous cardiovascular diseases,  and possible leukoplakia.  On August 27, 1997, after filing  sundry administrative complaints, Mr. Richardson filed this  complaint pro se in District Court seeking damages and  equitable relief under the FTCA and the Swine Flu Act.  In  his initial complaint, he alleged that the United States was  "negligent in this action, because the swine flu vaccine which  was administered to the Plaintiff was double the recommended dose for civilians or other non-military personnel."Id. p 18, reprinted in App. 8.


5
On November 12, 1997, the United States moved to dismiss  the action for lack of subject matter jurisdiction, making  three arguments.  First, the United States argued that the  Feres doctrine bars the claims under the FTCA.  See Feres v.  United States, 340 U.S. 135, 146 (1950) (precluding FTCA  liability for the Government for claims based on injuries that  "arise out of or are in the course of activity incident to  [military] service").  Alternatively, the Government argued  that the FTCA's statute of limitations bars Mr. Richardson's  claims.  Finally, the United States contended that the claims fall within the discretionary function exception to the FTCA,  see 28 U.S.C. § 2680(a), because Mr. Richardson challenged  discretionary policy-based decisions by asserting that the  military negligently administered a double-dose of the vaccine.


6
On December 9, 1997, Mr. Richardson filed a response to  the Government's motion to dismiss.  He asserted that he did  not seek compensation for tortious acts or omissions of military personnel, but for the "vaccine manufacture's [sic] tortious conduct, conduct that, absent the [Swine Flu] Act, would  give rise to a claim assertable directly against the manufacturer."  Resp. to Def.'s Mot. to Dismiss at 2, reprinted in  App. 38.  Mr. Richardson claimed that the vaccine manufacturer would be liable under local law absent the Swine Flu  Act, because it "produced a defective vaccine."  See id. at 3,  reprinted in App. 39.  Mr. Richardson denied basing his  claim on "any military order" and instead argued that his  claim was based on the defective or negligent manufacturing  of the vaccine.  See id. at 3-4, reprinted in App. 39-40 (citing  Hunt, 636 F.2d at 599 (holding that the Feres doctrine does  not apply to Swine Flu Act claims alleging injury from  negligently or defectively manufactured vaccine)).  Mr. Richardson also disputed the Government's argument regarding  his compliance with the statute of limitations.


7
On March 13, 1998, the District Court granted the Government's motion to dismiss on the ground that the discretionary  function exception barred the claim alleged in the original  complaint, but the court dismissed the complaint without  prejudice because the "basis for liability [alleged in the  original pro se complaint] may have been nothing more than a  pleading error."  Mem. Op. at 5, reprinted in App. 62.  The  District Court noted that, in response to the Government's  motion to dismiss, Mr. Richardson "broadly declares that he  was vaccinated with defective serum, but he does not allege  how the serum was defective other than it was double the  recommended dose."  Id. at 4, reprinted in App. 61.  The  District Court held that Mr. Richardson could not establish  liability based upon the military's decision to administer beyond the recommended dose.  See id. at 5, reprinted in  App. 62.


8
The District Court rejected the Government's argument  regarding the Feres doctrine, noting that dismissal on this  basis would directly conflict with Hunt.  See id. at 3, reprinted in App. 60.  It also rejected the Government's statute of  limitations argument, concluding that the complaint's allegations must be read in Mr. Richardson's favor as to when he  first discovered the cause of his alleged injuries.  See id.


9
On May 4, 1998, Mr. Richardson moved for an extension of  time to move for leave to file an amended complaint.  The  District Court denied the motion on May 6, 1998.  On May 7,  1998, Mr. Richardson filed a motion for leave to file an  amended complaint pursuant to Fed. R. Civ. P. 15(a), requesting leave to add new claims.  The proposed amended complaint filed with this motion indicates that Mr. Richardson  intended to replace his claim based on double-dosing with a  claim based on products liability.  See Amended Complaint  pp 20, 21, reprinted in App. 80-81.  The District Court denied  the motion on May 13, 1998, stating that Mr. Richardson  must first be granted a motion to alter or amend the judgment pursuant to Fed. R. Civ. P. 59(e) before he could file a  motion to amend the complaint.  Mr. Richardson filed separate notices of appeal from the order dismissing his case and  the order denying his motion for leave to amend.  On June  19, 1998, this court consolidated both appeals, and, on February 16, 1999, we appointed amicus curiae to argue in support  of Mr. Richardson.

II. Analysis

10
No one doubts that Mr. Richardson's original complaint  would properly be dismissed for lack of subject matter jurisdiction, because of the discretionary function exception.  See,  e.g., Hunt, 636 F.2d at 597 n.44 (stating that the "decision of  the military to administer a stronger-than-usual dose" can not  be a basis for liability under the Swine Flu Act).  The  question is whether Mr. Richardson fairly amended his complaint to add a claim based onproducts liability and, if so,  whether his claim was thereafter properly dismissed.


11
The District Court's opinion is open to two reasonable  interpretations.  First, the opinion can be read as dismissing  Mr. Richardson's complaint based on his original filing only,  disregarding the apparent change of course intended by Mr.  Richardson in adding a claim based on defective manufacturing.  Second, and less likely, the court's opinion can be read  as accepting Mr. Richardson's claim that he was bringing an  action based on products liability and dismissing the complaint nevertheless.  In either case, we reverse the District  Court.


12
A. The District Court's Treatment of Mr. Richardson's Re-ply to the Motion to Dismiss


13
On the record at hand, we hold that the District Court  abused its discretion in failing to consider Mr. Richardson's  complaint in light of his reply to the motion to dismiss.  See  Any anwutaku v. Moore, 151 F.3d 1053, 1059 (D.C. Cir. 1998).There are four factors that inform our holding that the  District Court erred in refusing to consider Mr. Richardson's  reply to constitute an amendment to his original complaint.


14
First, Mr. Richardson proceeded pro se before the District  Court.  Courts must construe pro se filings liberally.  See,  e.g., Haines v. Kerner, 404 U.S. 519, 520-21 (1972) (per  curiam) (holding allegations contained in a prisoner's pro se  complaint to less stringent standards than pleadings written  by counsel in reversing a dismissal for failure to state a  claim).  This point was recently emphasized in Anyanwutaku,  in which the District Court had dismissed a pro se complaint  sua sponte.  See 151 F.3d at 1054.  The plaintiff had initially  filed a "confusing" complaint that the District Court dismissed the same day it was filed.  See id.  After the dismissal, the plaintiff filed a motion for reconsideration and, subsequently, an " 'addendum' " to the motion.  See id.  The  District Court denied the motion for reconsideration.  See id.  at 1055.  This court reversed, reading all of the plaintiff's  filings together to conclude that the District Court abused its  discretion by denying the motion for reconsideration of its dismissal of one of the plaintiff's claims.  See id. at 1058-59.While Anyanwutaku involved the construction of a complaint  rather than amendment, here we similarly find that the  District Court should have read all of Mr. Richardson's filings  together before dismissing this case for lack of subject matter  jurisdiction.  See id. at 1059 ("[W]e think the district court  should have permitted his claim, drafted pro se and based on  legitimate factual allegations, to proceed."); see also Pearson  v. Gatto, 933 F.2d 521, 527 (7th Cir. 1991) (applying Haines to  hold that the District Court should have construed a pro se  plaintiff's letter to judge to be an amended complaint);  Cooper v. Sheriff, Lubbock County, Texas, 929 F.2d 1078, 1081  (5th Cir. 1991) (finding, in an appeal of a Fed. R. Civ. P.  12(b)(6) dismissal, that the magistrate judge should have  considered a pro se litigant's reply to the defendant's answer  as a motion to amend the complaint).


15
The second consideration guiding our decision is that, at  the time Mr. Richardson tendered his reply to the defendant's  motion to dismiss, he could have amended his claim as of  right because the defendant had filed no responsive pleading  and Mr. Richardson had never before sought amendment. See Fed. R. Civ. P. 15(a) (granting leave to amend once as "a  matter of course" at any time before a responsive pleading is  served);  Harris v. Secretary, United States Dep't of Veterans  Affairs, 126 F.3d 339, 344-45 (D.C. Cir. 1997) (recognizing  that amendments prior to a responsive pleading shall be  freely given under Rule 15(a)).  Moreover, courts freely grant  pro se litigants leave to amend.  See Moore v. Agency for  Int'l Dev., 994 F.2d 874, 877 (D.C. Cir. 1993).  Leave to  amend a complaint should be freely given in the absence of  undue delay, bad faith, undue prejudice to the opposing party,  repeated failure to cure deficiencies, or futility.  See Foman  v. Davis, 371 U.S. 178, 182 (1962).


16
The third factor that informs our decision is that the  District Court clearly understood that Mr. Richardson both  recognized the need for and attempted to make a change to  his original complaint.  In response to the motion to dismiss,  Mr. Richardson denied basing his claim on "any military  order" and instead clearly reframed his claim as one sounding in products liability, arguing that his injuries were caused by  the defective or negligent manufacturing of the vaccine.  See  Resp. to Def.'s Mot. to Dismiss at 3-4, reprinted in App. 3940.  The District Court recognized this, noting that Mr.  Richardson's response to the motion to dismiss "broadly  declares that he was vaccinated with defective serum, but he  does not allege how the serum was defective other than it was  double the recommended dose."  Mem. Op. at 4, reprinted in  App. 61.  Furthermore, the District Court itself acknowledged that the jurisdictional defect may simply be a matter of  a "pleading error."  Id. at 5, reprinted in App. 62.


17
Our last consideration is the lack of any evidence of prejudice to the Government if Mr. Richardson were allowed to  amend the complaint.  See Moore, 994 F.2d at 877-78 (noting  that a pro se litigant should be permitted to amend his  complaint to meet pleading requirements prior to dismissal so  long as the defendant is not prejudiced).  The Government  has made no argument here that it would have been prejudiced if the District Court had granted an amendment to Mr.  Richardson's complaint.


18
These factors, taken together, convince this court that Mr.  Richardson should be permitted to proceed with his claim. We do not suggest that a District Court must cull through  every filing of a pro se litigant to preserve a defective  complaint.  In this case, however, where, in addition to  proceeding pro se, the plaintiff retained the right to amend  his complaint prior to the dismissal, the plaintiff clearly  intended to add a new claim in his lawsuit, the District Court  apparently understood that the plaintiff both needed to and  wanted to do so, and the defendant would not have been  prejudiced by such amendment, we hold that the District  Court should have considered Mr. Richardson's reply to the  defendant's motion to dismiss to be an amendment to his  complaint.


19
B. The Adequacy of Mr. Richardson's Amended Complaint


20
As noted above, the District Court's opinion can be read as  accepting Mr. Richardson's reply to the defendant's motion to  dismiss as a de facto amendment to his original complaint, but  then dismissing the case because it found that Mr. Richardson made no factual allegation to support his claim except  that the serum was defective for being double the recommended dose.  See Mem. Op. at 4, reprinted in App. 61.Even on this reading, however, we find that the District  Court erred.


21
Mr. Richardson's amended complaint clearly stated a claim  sufficient to meet the Federal Rule of Civil Procedure's  liberal pleading requirements.  Indeed, at oral argument, the  Government's counsel was hard-pressed to contend otherwise.To survive a motion to dismiss for lack of subject matter  jurisdiction, a plaintiff is not required to plead facts sufficient  to prove his allegations;  rather, a court should only dismiss a  complaint for lack of subject matter jurisdiction if "it appears  beyond doubt that the plaintiff can prove no set of facts in  support of his claim which would entitle him to relief."Caribbean Broad. Sys., Ltd. v. Cable & Wireless PLC, 148  F.3d 1080, 1086 (D.C. Cir. 1998) (citations and internal quotation marks omitted).  Here, there is no indication that Mr.  Richardson can prove no set of facts entitling him to relief.In fact, the forms appended to the Federal Rules of Civil  Procedure clearly indicate that Mr. Richardson's complaint  meets liberal pleading requirements.  See Fed. R. Civ. P. app.  Form 2(c) (demonstrating requirements for statement of jurisdiction founded upon a particular statute);  id. Form 9  (demonstrating requirements for a complaint for negligence).


22
Moreover, as amicus points out, the complaint in Anyanwutaku was hardly less conclusory than the claim here.  See  Reply Br. of Amicus Curiae at 13.  In Anyanwutaku, the  claims found by the court to withstand dismissal alleged that  the plaintiff was "arbitrarily and capriciously denied access to  the said [prison] programs through invidious discrimination"  and that the defendants "invidiously discriminated against the  plaintiff based on race or ethnic origin."  Anyanwutaku, 151  F.3d at 1058 (alteration in original) (internal quotation marks  omitted).  These claims allege no more facts than does Mr.  Richardson's claim that he was injured by his exposure to a  defectively produced vaccine.  See Resp. to Def.'s Mot. to  Dismiss at 3-4, reprinted in App. 39-40.


23
We note, furthermore, that the discretionary function exception to the FTCA does not bar Swine Flu Act claims based  on the acts or omissions of the vaccine's provider.  See 42  U.S.C. § 247b(k)(2)(A)(ii) (1976) (revised and deleted 1978)  (making the exceptions in 28 U.S.C. § 2680(a) inapplicable to  actions based upon a program participant's act or omission).In addition, this circuit has held by implication that claims  against the Government that rely on products liability assertions against vaccine providers are permitted by the Swine  Flu Act.  See Hunt, 636 F.2d at 596 n.44, 599 (stating that  the Feres doctrine does not bar claims that would render a  vaccine manufacturer liable under local law on a theory of  strict products liability).  Therefore, the District Court's basis  for dismissing Mr. Richardson's original complaint based on  the United States military's negligence does not apply to his  amended claim based upon the vaccine manufacturer's defective production of the vaccine.


24
We need not consider the propriety of the District Court's  denial of Mr. Richardson's post-dismissal motion for leave to  amend his complaint.  Such a motion is typically only granted  where the litigant has first moved to amend or alter the  judgment under Fed. R. Civ. P. 59(e) or 60(b).  Mr. Richardson did not explicitly invoke either of these rules.  Because  we reverse the District Court's decision on other grounds, it  is not necessary to address Rule 59(e) or Rule 60(b).

III. Conclusion

25
For the reasons stated above, we reverse the District  Court's decision dismissing Mr. Richardson's complaint for  lack of subject matter jurisdiction and remand for proceedings consistent with this opinion.


26
So ordered.

